共查询到20条相似文献,搜索用时 15 毫秒
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Sidsel Ø. Andreasen Siow‐Feng Chong Mille B. L. Kryger Bettina E. B. Jensen Almar Postma Marie‐Helene Alves Brigitte Städler Kenneth N. Goldie Alexander N. Zelikin 《Particle & Particle Systems Characterization》2013,30(6):514-522
The assembly, cellular internalization, and cytotoxicity of nanoparticles based on physical hydrogels of poly(vinyl alcohol) (PVA) are reported. PVA nanoparticles are assembled using a liposomal templating technique followed by removal of the lipids using isopropanol, a process that requires the presence of a custom‐made block copolymer, poly(vinyl alcohol‐b‐vinyl pyrrolidone), to avoid aggregation of the nanoparticles. Polymer hydrogelation is induced via incubation in aqueous isopropyl alcohol solution, which results in PVA hydrogel nanoparticles (PVA HNP) with excellent colloidal stability and stability towards disintegration over at least 24 h. Pristine PVA HNP are found to be remarkably stealth‐like and exhibit negligible cellular internalization. This feature is likely inherent with the low fouling nature of PVA and makes PVA HNP attractive for targeted drug delivery with a low level of association with non‐targeted cells and tissues. Blending PVA with varied amounts of collagen results in colloidal hydrogel particles with a well pronounced tendency towards association with mammalian cells, specifically hepatocytes and endothelial cells. The association of PVA HNP elicits minimal changes in cellular proliferation, making these novel hydrogel particles convenient tools for drug delivery applications and creation of implantable artificial organelles and sensors. 相似文献
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Single-molecule studies have revealed molecular behaviors usually hidden in the ensemble and time averaging of bulk experiments.
Single-molecule measurement that can control physical form of individual DNA molecules is a powerful method to obtain new
knowledge about correlation between DNA-tension and enzyme activity. Here we study the effect of physical form of DNA on exonucleaseIII
(ExoIII) reaction. ExoIII has a double-stranded DNA specific 3′→5′ exonuclease activity and the digestion is distributive.
We observed the ExoIII digestion of individual stretched DNA molecules from the free ends. The sequentially captured photographs
demonstrated that the digested DNA molecule linearly shortened with the reaction time. We also carried out the single-molecule
observation under random coiled form by pausing the buffer flow. The digestion rates obtained from both single-molecule experiments
showed that the digestion rate under the stretched condition was two times higher than the random coiled condition. The correlation
between physical form of DNA and digestion rate of ExoIII was clearly demonstrated by single-molecule observations. 相似文献
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Poly(L-lactide-co-glycolide)(PLGA)copolymer (85/15) was prepared by direct-melt polycondensation instead of a ring-opening process. The polymer samples were hydrolyzed at 37°C in phosphate-buffered saline (PBS) for periods up to 10 weeks and the degradation behavior was characterized through weight average molecular mass change, mass loss, water uptake, and morphology. The results indicate that mass loss, weight average molecular mass, and water uptake of PLGA increase with increasing time; however, pH value of the PBS solution decreases. The degradation is heterogeneous—degradation in their central parts was faster than in the surface and regions due to the increased concentration of the acidic degradation products inside. 相似文献
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Murugesan Sankarganesh Jeyaraj Dhaveethu Raja Paul Raj Adwin Jose Gujuluva Gangatharan Vinoth Kumar Jegathalaprathaban Rajesh Ramalingam Rajasekaran 《Journal of fluorescence》2018,28(4):975-985
Biochemically active Cu(II) and Zn(II) complexes [CuL(ClO4)2(1) and ZnL(ClO4)2(2)] have been synthesized from N,N donor Schiff base ligand L derived from4,6-dichloropyrimdine-5-carboxaldehyde with 4-(2-aminoethyl)morpholine. The L, complexes 1 and 2 have been structurally characterized by elemental analysis, 1H-NMR, FTIR, MS, UV-Visible and ESR techniques. The results obtained from the spectral studies supports the complexes 1 and 2 are coordinated with L through square planar geometry. DFT calculations results supports, the ligand to metal charge transfer mechanism can occur between L and metal(II) ions. The antimicrobial efficacy results have been recommended that, complexes 1 and 2 are good anti-pathogenic agents than ligand L. The interaction of complexes 1 and 2 with calf thymus (CT) DNA has been studied by electronic absorption, viscometric, fluorometric and cyclic voltammetric measurements. The calculated Kb values for L, complexes 1 and 2 found from absorption titrations was 4.45?×?104, L; 1.92?×?105, 1 and 1.65?×?105, 2. The Ksv values were found to be 3.0?×?103, 3.68?×?103and 3.52?×?103 for L, complexes 1 and 2 by using competitive binding with ethidium bromide (EB). These results suggest that, the compounds are interacted with DNA may be electrostatic binding. The molecular docking studies have been carried out to confirm the interaction of compounds with DNA. Consequently, in vitro anticancer activities of L, complexes 1 and 2 against selected cancer (lung cancer A549, liver cancer HepG2 and cervical carcinoma HeLa) and normal (NHDF) cell lines were assessed by MTT assay. 相似文献
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Guanjun Chang Lin Zhang Runxiong Lin 《Journal of Macromolecular Science: Physics》2013,52(12):2499-2504
Six kinds of poly(imino ketone)s (PIKs) with different structures were designed, involving different ratios of carbonyl and imino groups, and the insertion of two types of bulky groups in the main chain. Under 3D periodic boundary conditions, simulations of physical and chemical properties for PIKs with six different structures on the molecular level, including fractional free volume (FFV) and melt density, solubility, and glass transition temperature, were carried out. 相似文献
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研究了一种新型轴向修饰硅酞菁,即二(2-氨基-6-三氟甲基-4-嘧啶氧基)硅酞菁(SiPcF)的光物理光化学性质、离体光动力抗癌活性以及与白蛋白的相互作用。结果表明,SiPcF的Q带最大吸收峰波长686 nm,摩尔吸光系数为2.3×105 mol-1·L ·cm-1,荧光发射峰694 nm,荧光量子产率为0.46,光敏化产生单线态氧的量子产率为0.38,是有效的1O2光敏剂。SiPcF与牛血清白蛋白(BSA)具有较强的相互作用,两者的结合常数为4.33×105mol·L-1,结合位点数为1。离体细胞实验表明,SiPcF具有较高的光动力抗癌活性,对人肝癌细胞HepG2的IC50值为5×10-7mol·L-1。 相似文献
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Hashemi Zahra Ebrahimzadeh Mohammad Ali Biparva Pourya 《Journal of fluorescence》2022,32(5):1669-1678
Journal of Fluorescence - A wide variety of medical, biomedical, and industrial applications has been reported for quinoxalines derivatives. In this work, a novel quinoxaline derivative was... 相似文献
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Nuclear and physical properties (activation and transmutation of elements) of BN and Al2O3 dielectric materials subjected to neutron irradiation for up to 5 years in Russian fast (BN-600) and fusion (DEMO-S) reactors were calculated using the ACDAM-2.0 software complex for different post-irradiation cooling times (up to 10 years). Analytical relations were derived for the calculated quantities. The results may be used in the analysis of properties of irradiated dielectric materials and may help establish the rules for safe handling of these materials. 相似文献
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光动力学疗法新型光敏剂的光谱特性研究 总被引:24,自引:1,他引:24
实验研究了用于光动力学诊断和治疗的新型光敏剂二磺基二邻苯二甲酰亚胺甲基酞菁锌(ZnPcS2P)癌光啉(PsD-007)、血啉甲醚(HMME)以及早期应用于临床的血卟啉衍生物(HpD)分别在生理盐水和含10%人血清生理盐水中的光谱特性。结果表明:除ZnPcS2P2的最大吸收峰位于670nm之外,其余三种光敏剂在人血清环境中的最大吸收峰都位于405nm处,但与生理盐水环境相比索瑞(Soret)峰发生了12nm的红移。在波长为413和514.5nm光源激发下,HMME,HpD和PsD-007在人血清环境中的荧光发射峰都分别位于625和690nm,但413nm光源的激发效率比514.5nm光源高出3倍左右,而且HEEM的荧光激发效率最高,HpD次之,PsD-007最低。 相似文献
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Bin Yang You-Lei Tu Shu-Xia Wang Shu-Chun Zhao Ru Xia Ming Cao 《Journal of Macromolecular Science: Physics》2018,57(4):266-277
Carbon nano-tube (CNT)- and carbon fiber (CF)-filled polyolefin nano-composites were prepared by melt blending. The water absorption, expansion ratio, electrical conductivities, and physical and mechanical properties of the prepared nano-composites were extensively investigated. The experimental results showed that the water absorption increased with the elapsed time from the starting point when the samples were immersed into the water. The linear expansion ratios of the composites were found to increase gradually with time till reaching an equilibrium value. Composites with excellent dielectric properties could be obtained when the filler content was above the percolation threshold. The addition of CNT and CF resulted in no obvious improvement in mechanical properties in the present study, but both Shore hardness and Vicat softening temperature (VST) of the composites increased with increasing filler content. The present work will be of practical importance to the CNT/CF filler composites design, and optimization of processing variables, as well as the further exploration of the “processing-structure-property” relationship of polyolefin materials. 相似文献
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为深入认识高铁化合物的物理性质和电化学性能,采用化学法合成了K2FeO4、BaFeO4、SrFeO4和 K2Sr(FeO4)2等几种高铁化合物,比较研究了这几种高铁化合物的形貌、结构、在不同浓度KOH溶液中的溶解度 及其放电性能.研究结果显示,在这几种高铁化合物中,BaFeO4具有较好的电化学性能.但在实验过程中发现,除 K2FeO4外,其余几种高铁化合物均不稳定,在干燥环境中放置时会发生分解.采用量子化学从头算方法从理论上 分析了高铁化合物的稳定性变化规律.研究结果表明,高铁化合物的稳定性与阳离子对FeO42-的极化作用有很 大关系,极化作用越强,高铁化合物就越不稳定. 相似文献